The total postage cost is determined by the weight of your mailpiece, its dimensions, and the selected USPS service. Additional services like tracking or insurance will increase the price. This calculator provides an estimate based on standard rates.
Letter
Postcard
Flat (Large Envelope)
Package
Select the type of mailpiece you are sending.
Enter the weight in ounces (oz). For packages, this may be pounds (lbs), which will be converted.
Ounces (oz)
Pounds (lbs)
Specify the unit for package weight.
For flats and packages, enter L x W x H (inches). Required for some package services.
First-Class Mail Letter
First-Class Mail Postcard
First-Class Mail Flat
Priority Mail
Priority Mail Express
USPS Ground Advantage
Choose the desired shipping service.
Helps estimate specific zone-based pricing for packages.
Understanding the USPS Stamp Calculator
What is a USPS Stamp Calculator?
A USPS Stamp Calculator is an online tool designed to help individuals and businesses estimate the cost of sending mail and packages through the United States Postal Service (USPS). It takes into account various factors like the weight, dimensions, destination, and the chosen shipping service to provide an accurate postage price. The primary function of a USPS stamp calculator is to simplify the often complex pricing structures of the USPS, ensuring users pay the correct postage and avoid potential surcharges or delays due to insufficient postage. It's an essential tool for anyone who frequently mails items, from personal correspondence to business shipments, helping them budget effectively and choose the most cost-efficient shipping method. Understanding how to use this calculator is key to managing mailing expenses.
This tool is particularly useful for:
Small businesses managing shipping costs for e-commerce orders.
Individuals sending gifts, letters, or documents domestically and internationally.
Anyone comparing different USPS shipping services (e.g., First-Class Mail vs. Priority Mail).
Users needing to estimate postage for non-standard mail pieces like large envelopes or packages.
Common misconceptions about USPS pricing include the belief that all letters cost the same regardless of weight (up to 3.5 oz for First-Class), or that package pricing is solely based on weight without considering dimensions or distance. A reliable USPS Stamp Calculator clarifies these points by applying the official USPS rate tables.
USPS Postage Calculation Formula and Explanation
Calculating USPS postage involves several variables, and the exact formula can be complex due to different service levels, surcharges, and discounts. However, a generalized approach used by a USPS Stamp Calculator can be understood as follows:
Base Cost = (Standard Rate for Mail Type/Service) + (Weight Adjustment) + (Dimensional Adjustment) + (Zone Adjustment)
Let's break down the key components:
Mail Type & Service: Different categories (Letter, Postcard, Flat, Package) and services (First-Class Mail, Priority Mail, USPS Ground Advantage) have distinct base rates. Letters have a base rate for the first ounce, with additional charges per ounce thereafter. Packages often have rates based on weight, size, and distance (zone).
Weight: The actual weight of the mailpiece is a primary factor. For First-Class Mail letters, there's a cost per ounce. For packages, weight determines the price tier within a specific zone. The USPS USPS Stamp Calculator must accurately convert weights if needed (e.g., pounds to ounces).
Dimensions: For Flats (larger envelopes) and Packages, length, width, and height are critical. Oversized items or those exceeding specific dimensional limits may incur surcharges or require specific services. Some services use "dimensional weight" if it exceeds the actual weight.
Destination (Zone): For packages and some other services, the distance from the origin ZIP code to the destination ZIP code determines the "zone." Postage costs increase with the zone number. Many calculators use a sample ZIP or allow user input for better accuracy.
Additional Services: Fees for services like Certified Mail, Return Receipts, Insurance, Signature Confirmation, etc., are added on top of the base postage.
Variables Table for USPS Postage Calculation
Variable Name
Meaning
Unit
Typical Range / Notes
Mail Type
Category of mailpiece
N/A
Letter, Postcard, Flat, Package
Weight
Actual weight of the mailpiece
Ounces (oz) or Pounds (lbs)
Letters: up to 3.5 oz (First-Class). Packages: 0.1 oz upwards. 1 lb = 16 oz.
Dimensions
Length, Width, Height
Inches (in)
Letters: standard sizes. Flats: up to 15″ x 12″ x 1.75″. Packages: Varies, subject to USPS limits (e.g., max 108″ combined length + girth).
Service Type
Selected USPS shipping speed and class
N/A
First-Class Mail, Priority Mail, USPS Ground Advantage, etc.
Destination ZIP Code
Originating ZIP code for zone calculation
ZIP Code (5-digit)
00501 to 96999. Used to determine shipping zones for packages.
Volume
Number of pieces being mailed (for bulk mail)
Count
Applies primarily to commercial mailers, not typical calculator use.
Additional Services
Extra features requested
N/A
Tracking, Insurance, Signature Confirmation, etc.
Practical Examples of Using the USPS Stamp Calculator
Example 1: Sending a Standard First-Class Mail Letter
Scenario: You need to mail a standard business letter (e.g., a bill or a personal letter) within your home state.
Inputs:
Type of Mail: Letter
Weight: 2 oz
Dimensions: Not applicable (standard letter size)
USPS Service: First-Class Mail Letter
Destination ZIP Code: Not critical for standard letter rates.
Calculator Output:
Weight: 2 oz
Size: Standard Letter
Service: First-Class Mail
Estimated Postage Cost: $0.69 (Cost of one Forever Stamp + $0.24 for the additional ounce, based on current rates)
Interpretation: The USPS Stamp Calculator shows that a 2 oz First-Class Mail letter will cost $0.69. This means a standard Forever Stamp (currently covering the first ounce) plus an additional ounce stamp or equivalent postage is needed.
Example 2: Shipping a Small Package via USPS Ground Advantage
Scenario: You are selling a small, lightweight item online and need to ship it using a more economical service.
Inputs:
Type of Mail: Package
Weight: 1 lb 4 oz (which is 20 oz)
Weight Unit: Pounds (lbs)
Dimensions: 8 x 6 x 3 inches
USPS Service: USPS Ground Advantage
Destination ZIP Code: 10001 (New York) from origin ZIP 90210 (Los Angeles) – this implies Zone 8.
Calculator Output:
Weight: 20 oz
Size: Package
Service: USPS Ground Advantage
Estimated Postage Cost: ~$8.50 (This is an approximation; actual cost depends heavily on the zone. The calculator would show the specific zone rate for Zone 8, 1-2 lb category).
Interpretation: The USPS Stamp Calculator helps determine that for a 20 oz package going coast-to-coast (Zone 8), USPS Ground Advantage is a viable option. The cost is significantly less than Priority Mail for longer distances, but transit times will be longer. The calculator helps make this trade-off clear.
Select Mail Type: Choose whether you are sending a Letter, Postcard, Flat (large envelope), or Package. This is the most crucial first step as it dictates the available options and pricing structure.
Enter Weight: Input the weight of your mailpiece. For letters and postcards, this is typically in ounces. For packages, you might need to specify if the weight is in ounces or pounds. Ensure accuracy, as exceeding weight limits can result in significant surcharges.
Input Dimensions (If Applicable): For Flats and Packages, enter the Length, Width, and Height in inches. The calculator uses this information to check for size restrictions and potential dimensional weight calculations, especially for larger packages.
Choose USPS Service: Select the desired shipping speed and service level (e.g., First-Class Mail for lightweight items, Priority Mail for faster delivery, USPS Ground Advantage for economical ground shipping).
Enter Destination ZIP Code (Optional but Recommended for Packages): Providing the destination ZIP code allows the calculator to estimate costs based on shipping zones, which is critical for package pricing.
View Results: The calculator will instantly display the estimated postage cost, along with intermediate details like the weight, size category, and service selected.
Interpreting Results: The primary result is the estimated total postage cost. The intermediate results provide context. Always remember that this is an estimate. Final costs may vary slightly due to rounding, specific surcharges not included in the basic calculator logic (like oddly shaped items), or mail offered at a Post Office™ retail counter versus online postage. For precise commercial pricing, consult USPS Commercial Pricing information.
Decision-Making Guidance: Use the results to compare different service levels. If cost is the main concern, opt for slower services like USPS Ground Advantage or First-Class Mail for lighter items. If speed is essential, Priority Mail or Priority Mail Express are better choices, albeit more expensive. The USPS Stamp Calculator empowers informed decisions about your shipping needs.
Key Factors Affecting USPS Postage Costs
Several factors influence the final price you pay for USPS postage. Understanding these is vital for accurate cost estimation and management using a USPS Stamp Calculator:
Weight: This is the most fundamental factor. Postage rates increase incrementally with weight, especially for letters and flats within First-Class Mail. Packages are categorized into weight bands (e.g., 1 lb, 2 lbs, 3-5 lbs, etc.). Accurate weighing is crucial.
Dimensions (Length, Width, Height): For packages and large envelopes (Flats), dimensions matter significantly. USPS uses size categories (e.g., Large Flat, Large Package) and can apply dimensional weight pricing. If dimensional weight exceeds actual weight, you pay for the higher of the two. Large packages also incur higher rates and size limits.
Destination & Distance (Zones): For packages and Priority Mail, the distance between the origin and destination ZIP codes determines the shipping "zone." Prices increase substantially with each zone, with Zone 8 (coast-to-coast) being the most expensive. A good USPS Stamp Calculator factors this in.
Service Type: The speed and reliability required dictate the service. First-Class Mail is economical for lightweight items. USPS Ground Advantage offers a balance of cost and speed for packages. Priority Mail and Priority Mail Express provide faster, guaranteed delivery times but at a higher cost.
Mail Shape & Usability: Letters, postcards, and flats have different size and thickness standards. Items that don't meet the standard letter or flat criteria (e.g., rigid items, irregularly shaped pieces) may be classified as packages and priced accordingly, often with higher rates.
Additional Services: Features like tracking, delivery confirmation, signature confirmation, insurance, Certified Mail, and Return Receipt add to the base postage cost. These provide added security and verification but increase the total price.
Volume & Discounts (Commercial Mailers): While not typically used by individuals, businesses sending large volumes of mail may qualify for commercial pricing, bulk mail discounts, or presort services, significantly reducing per-piece costs. This advanced USPS Stamp Calculator focuses on standard retail rates.
Fuel Surcharges & Economic Factors: While not always explicitly itemized on retail receipts, USPS rates can be influenced by economic conditions, fuel costs, and USPS operational adjustments. These are generally baked into the official rate tables used by the calculator.
Frequently Asked Questions (FAQ)
Q1: What is the standard price for a USPS stamp?
A: As of early 2024, the price for a single Forever Stamp (covering the first ounce of a First-Class Mail letter) is $0.68. Additional ounces cost $0.24 each. Prices are subject to change by the USPS.
Q2: How much does it cost to send a postcard?
A: The price for a First-Class Mail postcard is $0.53. Postcards have specific size and thickness requirements (4×6 inches is a common size).
Q3: What is the maximum weight for a First-Class Mail letter?
A: First-Class Mail letters can weigh up to 3.5 ounces. Anything heavier must be sent as a Flat or Package, typically starting with USPS Ground Advantage or Priority Mail.
Q4: How does USPS calculate package weight if I use pounds?
A: USPS often rounds up to the next pound for pricing heavier packages. For example, a 1 lb 4 oz package might be priced in the 2 lb category depending on the service. Our USPS Stamp Calculator converts lbs to oz for internal calculations and applies appropriate weight breaks.
Q5: What's the difference between USPS Ground Advantage and Priority Mail?
A: USPS Ground Advantage is generally more economical and has longer delivery times (typically 2-5 business days depending on distance). Priority Mail offers faster delivery (typically 1-3 business days) and includes $100 of insurance for most shipments. The USPS Stamp Calculator helps compare these costs.
Q6: Do dimensions matter for letters?
A: For standard First-Class Mail letters, only weight (up to 3.5 oz) and postage are the primary concerns. However, letters that are too thick (rigid) or have unusual shapes might be classified as flats or packages and cost more.
Q7: Can I use the calculator for international mail?
A: This specific USPS Stamp Calculator is designed for domestic shipments within the United States. International rates are significantly different and depend on the destination country, service, and weight.
Q8: What happens if I put the wrong postage on my mail?
A: If you underpay, your mail may be returned to sender, delayed until the recipient pays the difference, or potentially confiscated depending on the service and value. Using an accurate USPS Stamp Calculator helps prevent this.
Q9: Does the calculator include insurance costs?
A: This calculator primarily estimates the base postage cost for the selected service. Additional insurance purchased separately at the Post Office or online will increase the total cost. Priority Mail includes a base amount of insurance.
var baseRates = {
letter: {
first_class: { base: 0.68, per_oz: 0.24, max_oz: 3.5 },
// Add other letter classes if needed
},
postcard: {
first_class: { base: 0.53, max_oz: 4, dimension_max_l: 6, dimension_max_w: 4.25 },
},
flat: {
first_class: { base: 1.35, per_oz: 0.24, max_oz: 15.99, dimension_max_l: 15, dimension_max_w: 12, dimension_max_h: 1.75 },
// Add other flat classes if needed
},
package: {
// Using simplified weights for common services. Real rates are zone-based.
// Weight tiers (oz): 1-8, 9-12, 13-15.99, 16-32, 32.01-48, 48.01-64, 64.01-70.4
// Using simplified lb tiers for packages: 1lb, 2lb, 3lb, 4lb, 5lb, 6lb, 70lb max
usps_ground_advantage: [
{ lb: 1, rate_zone: [4.95, 5.15, 5.45, 5.75, 6.15, 6.55, 7.15, 7.95] }, // Zone 1-2, 3, 4, 5, 6, 7, 8
{ lb: 2, rate_zone: [5.85, 6.15, 6.55, 7.05, 7.55, 8.15, 8.95, 9.95] },
{ lb: 3, rate_zone: [6.75, 7.25, 7.75, 8.35, 8.95, 9.65, 10.55, 11.75] },
{ lb: 4, rate_zone: [7.65, 8.25, 8.85, 9.55, 10.25, 11.05, 12.05, 13.25] },
{ lb: 5, rate_zone: [8.55, 9.35, 10.05, 10.85, 11.65, 12.55, 13.75, 15.15] },
{ lb: 6, rate_zone: [9.45, 10.45, 11.25, 12.15, 13.05, 14.05, 15.45, 16.95] },
// Simplified: Add more tiers up to 70 lbs if needed. Real rates are complex.
// For this calculator, we'll use a lookup for common weight tiers.
],
priority: [ // Priority Mail Small Flat Rate Box rates are often simpler, but let's use general pricing
{ lb: 1, rate_zone: [8.05, 8.35, 8.75, 9.25, 9.85, 10.45, 11.25, 12.35] },
{ lb: 2, rate_zone: [8.55, 9.15, 9.55, 10.15, 10.85, 11.55, 12.45, 13.65] },
{ lb: 3, rate_zone: [9.15, 9.85, 10.35, 10.95, 11.75, 12.55, 13.55, 14.95] },
{ lb: 4, rate_zone: [9.75, 10.55, 11.15, 11.85, 12.65, 13.55, 14.65, 16.25] },
{ lb: 5, rate_zone: [10.35, 11.25, 11.95, 12.75, 13.55, 14.55, 15.75, 17.55] },
// Simplified: Add more tiers up to 70 lbs.
],
priority_express: [ // Express rates are generally higher
{ lb: 1, rate_zone: [26.95, 27.55, 28.25, 29.05, 29.85, 30.65, 31.55, 32.85] },
{ lb: 2, rate_zone: [29.95, 30.75, 31.45, 32.35, 33.25, 34.15, 35.15, 36.75] },
// Simplified rates, real pricing is complex
]
}
};
var defaultRates = {
letter: {
first_class: { base: 0.68, per_oz: 0.24, max_oz: 3.5 },
},
postcard: {
first_class: { base: 0.53, max_oz: 4, dimension_max_l: 6, dimension_max_w: 4.25 },
},
flat: {
first_class: { base: 1.35, per_oz: 0.24, max_oz: 15.99, dimension_max_l: 15, dimension_max_w: 12, dimension_max_h: 1.75 },
},
package: {
usps_ground_advantage: [
{ lb: 1, rate_zone: [4.95, 5.15, 5.45, 5.75, 6.15, 6.55, 7.15, 7.95] },
{ lb: 2, rate_zone: [5.85, 6.15, 6.55, 7.05, 7.55, 8.15, 8.95, 9.95] },
{ lb: 3, rate_zone: [6.75, 7.25, 7.75, 8.35, 8.95, 9.65, 10.55, 11.75] },
{ lb: 4, rate_zone: [7.65, 8.25, 8.85, 9.55, 10.25, 11.05, 12.05, 13.25] },
{ lb: 5, rate_zone: [8.55, 9.35, 10.05, 10.85, 11.65, 12.55, 13.75, 15.15] },
{ lb: 6, rate_zone: [9.45, 10.45, 11.25, 12.15, 13.05, 14.05, 15.45, 16.95] },
],
priority: [
{ lb: 1, rate_zone: [8.05, 8.35, 8.75, 9.25, 9.85, 10.45, 11.25, 12.35] },
{ lb: 2, rate_zone: [8.55, 9.15, 9.55, 10.15, 10.85, 11.55, 12.45, 13.65] },
{ lb: 3, rate_zone: [9.15, 9.85, 10.35, 10.95, 11.75, 12.55, 13.55, 14.95] },
{ lb: 4, rate_zone: [9.75, 10.55, 11.15, 11.85, 12.65, 13.55, 14.65, 16.25] },
{ lb: 5, rate_zone: [10.35, 11.25, 11.95, 12.75, 13.55, 14.55, 15.75, 17.55] },
],
priority_express: [
{ lb: 1, rate_zone: [26.95, 27.55, 28.25, 29.05, 29.85, 30.65, 31.55, 32.85] },
{ lb: 2, rate_zone: [29.95, 30.75, 31.45, 32.35, 33.25, 34.15, 35.15, 36.75] },
]
}
};
// Dummy zone lookup. Realistically, this would involve complex calculations or a lookup table.
// For simplicity, we'll map ZIP code ranges to zones and use a default if no ZIP is provided.
function getZone(destinationZip) {
if (!destinationZip || typeof destinationZip !== 'string' || destinationZip.length !== 5 || isNaN(destinationZip)) {
return 5; // Default to a mid-range zone if input is invalid or missing
}
var zip = parseInt(destinationZip);
// Very simplified zone mapping for demonstration
if (zip >= 1000 && zip = 1801 && zip = 3000 && zip = 4000 && zip = 5000 && zip = 7000 && zip = 8000 && zip = 9000 && zip = 9610 && zip <= 96999) return 8; // e.g., Far West / AK / HI (simplified)
return 5; // Default zone
}
function getPackageWeightTier(weightOz) {
if (weightOz < 16) return 0; // 1-15.99 oz, handled separately or priced as 1lb tier
if (weightOz < 32) return 1; // 1 lb tier
if (weightOz < 48) return 2; // 2 lb tier
if (weightOz < 64) return 3; // 3 lb tier
if (weightOz < 70.4) return 4; // 4 lb tier (up to 64oz, or 4lbs)
// simplified further for demo
if (weightOz <= 16) return 0; // Treat 1 to 16oz as 1lb category base
if (weightOz <= 32) return 1; // 2lb
if (weightOz <= 48) return 2; // 3lb
if (weightOz <= 64) return 3; // 4lb
if (weightOz <= 80) return 4; // 5lb
if (weightOz <= 96) return 5; // 6lb
// Above 70 lbs becomes very expensive and requires different handling
if (weightOz <= 70*16) return 6; // up to 70 lbs
return 6; // Cap at 70lb tier for simplicity
}
function getPackageWeightTierForLookup(weightOz) {
if (weightOz <= 16) return 0; // Maps to the 1lb rate array index
if (weightOz <= 32) return 1; // Maps to the 2lb rate array index
if (weightOz <= 48) return 2; // Maps to the 3lb rate array index
if (weightOz <= 64) return 3; // Maps to the 4lb rate array index
if (weightOz <= 80) return 4; // Maps to the 5lb rate array index
if (weightOz <= 96) return 5; // Maps to the 6lb rate array index
if (weightOz <= 70*16) return 6; // Maps to the 70lb rate array index
return 6; // Default to highest defined tier if over
}
function calculatePostage() {
var mailType = document.getElementById('mailType').value;
var weight = parseFloat(document.getElementById('weight').value);
var weightUnit = document.getElementById('packageWeightUnit').value;
var dimensions = document.getElementById('dimensions').value;
var serviceType = document.getElementById('serviceType').value;
var destinationZip = document.getElementById('destinationZip').value;
// Reset errors
document.getElementById('weightError').textContent = '';
document.getElementById('dimensionsError').textContent = '';
document.getElementById('zipError').textContent = '';
var postageCost = 0;
var weightOz = weight;
var mailSize = 'Standard'; // Default
var effectiveService = serviceType; // Can be overridden by mail type logic
// — Input Validation —
if (isNaN(weight) || weight 70 * 16) { // USPS max weight for most packages is 70 lbs
document.getElementById('weightError').textContent = 'Package weight exceeds USPS limit (70 lbs).';
return { cost: 0, weightOz: weightOz, mailSize: 'Oversized', service: 'Invalid' };
}
// Parse dimensions for flats and packages
var dimParts = [];
var length = 0, width = 0, height = 0;
if (dimensions) {
dimParts = dimensions.toLowerCase().split(/[x]/).map(function(part) { return parseFloat(part.trim()); });
if (dimParts.length === 3 && !isNaN(dimParts[0]) && !isNaN(dimParts[1]) && !isNaN(dimParts[2])) {
length = dimParts[0];
width = dimParts[1];
height = dimParts[2];
// Sort dimensions to easily check max values
var sortedDims = [length, width, height].sort(function(a, b){ return b – a; });
length = sortedDims[0]; // Longest
width = sortedDims[1];
height = sortedDims[2];
} else if (mailType === 'flat' || mailType === 'package') {
document.getElementById('dimensionsError').textContent = 'Invalid format. Use L x W x H (e.g., 10x8x2 inches).';
// Allow calculation to proceed but flag potential issue
}
}
var zipCodeValid = /^\d{5}$/.test(destinationZip);
if (mailType === 'package' && destinationZip && !zipCodeValid) {
document.getElementById('zipError').textContent = 'Invalid ZIP code format.';
}
// — Rate Calculation Logic —
if (mailType === 'letter') {
mailSize = 'Letter';
effectiveService = 'firstclass_letter';
var letterRates = defaultRates.letter.first_class;
if (weightOz <= 1) {
postageCost = letterRates.base;
} else if (weightOz 0 && postageCost postcardRates.max_oz) {
document.getElementById('weightError').textContent = 'Postcard exceeds maximum weight (4 oz).';
return { cost: 0, weightOz: weightOz, mailSize: 'Postcard (Overweight)', service: 'N/A' };
}
// Check dimensions for postcard eligibility
if (length > postcardRates.dimension_max_l || width > postcardRates.dimension_max_w) {
// If dimensions are too large, it's not a postcard rate. Assume it's a Flat or Letter.
// For simplicity, we'll guide user to Flat/Letter.
mailSize = 'Large Postcard Size'; // Indicate potential issue
document.getElementById('dimensionsError').textContent = 'Dimensions exceed postcard limits. Consider Flat rate.';
// Fallback to letter rate if it fits basic letter criteria, otherwise might need Flat
if (weightOz <= 1) postageCost = defaultRates.letter.first_class.base;
else postageCost = defaultRates.letter.first_class.base + Math.ceil(weightOz – 1) * defaultRates.letter.first_class.per_oz;
effectiveService = 'firstclass_letter'; // Reclassify
} else {
postageCost = postcardRates.base;
}
}
else if (mailType === 'flat') {
mailSize = 'Flat';
effectiveService = 'firstclass_flat';
var flatRates = defaultRates.flat.first_class;
if (weightOz <= 1) {
postageCost = flatRates.base;
} else if (weightOz flatRates.dimension_max_l || width > flatRates.dimension_max_w || height > flatRates.dimension_max_h) {
document.getElementById('dimensionsError').textContent = 'Dimensions exceed Flat rate limits (15″x12″x1.75″). Consider Package rate.';
// If dimensions are too large, it may need to be priced as a package.
// For simplicity, we'll try to price it as a package using the selected service type IF it's a package service
if (serviceType.startsWith('priority') || serviceType === 'usps_ground_advantage') {
effectiveService = serviceType; // Use the selected package service
} else {
// If user selected First-Class Flat service but dimensions are too big, it's ambiguous.
// We'll default to a higher base for large flats conceptually, or guide to package.
// For now, let's just show an error and maybe a higher effective rate.
postageCost = Math.max(postageCost, 3.00); // Arbitrary higher base for oversized flat needing package handling
effectiveService = 'Oversized Flat';
}
}
if (postageCost > 0 && postageCost = rates.length || zoneIndex >= rates[tierIndex].rate_zone.length) {
document.getElementById('weightError').textContent = 'Weight or zone out of calculated range for this service.';
return { cost: 0, weightOz: weightOz, mailSize: 'Package', service: serviceType };
}
postageCost = rates[tierIndex].rate_zone[zoneIndex];
// Dimensional weight check for packages (simplified)
// Length + Girth (2*Width + 2*Height)
var girth = (2 * width) + (2 * height);
var combinedLg = length + girth;
// USPS limits: Max length 108″, max combined 130″ for most standard packages
if (length > 60 || combinedLg > 130) { // Exaggerated length limit for demo
document.getElementById('dimensionsError').textContent = 'Package dimensions exceed USPS limits (Max Length 108″, Max L+Girth 130″).';
postageCost = 0; // Invalid
} else if (combinedLg > 108) { // Use higher rates for large packages (>108″)
// Simplified: Add a surcharge or use different rate table. For demo, let's say add $10
postageCost += 10.00;
mailSize = 'Large Package';
}
} else if (serviceType === 'priority') {
var rates = defaultRates.package.priority;
var tierIndex = getPackageWeightTierForLookup(weightOz);
if (tierIndex >= rates.length || zoneIndex >= rates[tierIndex].rate_zone.length) {
document.getElementById('weightError').textContent = 'Weight or zone out of calculated range for this service.';
return { cost: 0, weightOz: weightOz, mailSize: 'Package', service: serviceType };
}
postageCost = rates[tierIndex].rate_zone[zoneIndex];
var girth = (2 * width) + (2 * height);
var combinedLg = length + girth;
if (length > 60 || combinedLg > 130) {
document.getElementById('dimensionsError').textContent = 'Package dimensions exceed USPS limits (Max Length 108″, Max L+Girth 130″).';
postageCost = 0;
} else if (combinedLg > 108) {
postageCost += 10.00;
mailSize = 'Large Package';
}
} else if (serviceType === 'priority_express') {
var rates = defaultRates.package.priority_express;
var tierIndex = getPackageWeightTierForLookup(weightOz);
if (tierIndex >= rates.length || zoneIndex >= rates[tierIndex].rate_zone.length) {
document.getElementById('weightError').textContent = 'Weight or zone out of calculated range for this service.';
return { cost: 0, weightOz: weightOz, mailSize: 'Package', service: serviceType };
}
postageCost = rates[tierIndex].rate_zone[zoneIndex];
var girth = (2 * width) + (2 * height);
var combinedLg = length + girth;
if (length > 60 || combinedLg > 130) {
document.getElementById('dimensionsError').textContent = 'Package dimensions exceed USPS limits (Max Length 108″, Max L+Girth 130″).';
postageCost = 0;
} else if (combinedLg > 108) {
postageCost += 10.00;
mailSize = 'Large Package';
}
}
else {
// Handle other package services if added
postageCost = 5.00; // Default minimum for unknown package service
}
}
// Cap invalid costs at 0
if (postageCost < 0) postageCost = 0;
return { cost: postageCost, weightOz: weightOz, mailSize: mailSize, service: effectiveService, zone: zone };
}
function updateCalculator() {
var validationResult = calculatePostage();
var cost = validationResult.cost;
var weightOz = validationResult.weightOz;
var mailSize = validationResult.mailSize;
var service = validationResult.service;
var zone = validationResult.zone;
document.getElementById('primary-result').textContent = '$' + cost.toFixed(2);
document.getElementById('weightResult').innerHTML = 'Weight: ' + weightOz.toFixed(2) + ' oz';
document.getElementById('sizeResult').innerHTML = 'Size: ' + mailSize + '';
document.getElementById('serviceResult').innerHTML = 'Service: ' + service.replace(/_/g, ' ').replace('firstclass', 'First-Class').replace('usps', 'USPS') + '';
// Update intermediate results based on calculations
if (service && service.includes('package')) {
document.getElementById('serviceResult').innerHTML += ` (Zone ${zone})`;
}
updateChart(validationResult); // Update chart data
updateTable(validationResult); // Update table data
}
function resetCalculator() {
document.getElementById('mailType').value = 'letter';
document.getElementById('weight').value = '1';
document.getElementById('packageWeightUnit').value = 'oz';
document.getElementById('packageWeightUnitGroup').style.display = 'none';
document.getElementById('dimensions').value = ";
document.getElementById('serviceType').value = 'firstclass_letter';
document.getElementById('destinationZip').value = ";
// Reset errors
document.getElementById('weightError').textContent = ";
document.getElementById('dimensionsError').textContent = ";
document.getElementById('zipError').textContent = ";
updateCalculator(); // Recalculate with default values
}
function copyResults() {
var result = document.getElementById('primary-result').textContent;
var weight = document.getElementById('weightResult').textContent.replace('Weight: ', ");
var size = document.getElementById('sizeResult').textContent.replace('Size: ', ");
var service = document.getElementById('serviceResult').textContent.replace('Service: ', ");
var summary = `USPS Postage Estimate:\n${service}\n${weight}\n${size}\n\nEstimated Cost: ${result}`;
// Use navigator.clipboard for modern browsers
if (navigator.clipboard && navigator.clipboard.writeText) {
navigator.clipboard.writeText(summary).then(function() {
alert('Results copied to clipboard!');
}).catch(function(err) {
console.error('Could not copy text: ', err);
// Fallback for older browsers or if clipboard API fails
fallbackCopyTextToClipboard(summary);
});
} else {
fallbackCopyTextToClipboard(summary);
}
}
function fallbackCopyTextToClipboard(text) {
var textArea = document.createElement("textarea");
textArea.value = text;
textArea.style.position="fixed";
textArea.style.left="-9999px";
textArea.style.top="-9999px";
document.body.appendChild(textArea);
textArea.focus();
textArea.select();
try {
var successful = document.execCommand('copy');
var msg = successful ? 'Results copied to clipboard!' : 'Failed to copy results.';
alert(msg);
} catch (err) {
console.error('Fallback: Oops, unable to copy', err);
alert('Failed to copy results. Please copy manually.');
}
document.body.removeChild(textArea);
}
// — Charting —
var myChart;
var chartContext = document.getElementById('postageChart').getContext('2d');
function updateChart(calcResult) {
// Basic chart showing cost breakdown if applicable, or cost vs weight
var chartData = {
labels: [],
datasets: []
};
var cost = calcResult.cost;
var weightOz = calcResult.weightOz;
var service = calcResult.service;
var mailType = document.getElementById('mailType').value;
if (mailType === 'letter' && service === 'firstclass_letter') {
chartData.labels = ['Base (1 oz)', 'Additional Oz'];
var baseCost = defaultRates.letter.first_class.base;
var additionalOzCost = cost – baseCost;
if (additionalOzCost 108) {
surcharge = 10.00; // Match the surcharge added in calculation
}
}
}
chartData.datasets.push({
label: 'Package Cost Components',
data: [baseRate – surcharge, surcharge], // Adjust base rate down to show surcharge clearly
backgroundColor: ['#004a99', '#ffc107'],
borderColor: '#ffffff',
borderWidth: 1
});
} else {
// Default chart: Cost vs Weight (simplified)
chartData.labels = ['Current Weight'];
chartData.datasets.push({
label: 'Estimated Cost',
data: [cost],
backgroundColor: '#004a99',
borderColor: '#ffffff',
borderWidth: 1
});
}
if (myChart) {
myChart.destroy();
}
myChart = new Chart(chartContext, {
type: 'bar',
data: chartData,
options: {
responsive: true,
maintainAspectRatio: false,
scales: {
y: {
beginAtZero: true,
ticks: {
callback: function(value) {
return '$' + value.toFixed(2);
}
}
}
},
plugins: {
legend: {
display: true,
position: 'top',
},
title: {
display: true,
text: 'Postage Cost Breakdown / Estimate'
}
}
}
});
}
// — Table Data —
function updateTable(calcResult) {
// For this calculator, a complex table isn't strictly necessary unless showing yearly/amortization
// Let's create a simple table summarizing the inputs and outputs.
var tableBody = document.getElementById('calculationDetailsBody');
tableBody.innerHTML = "; // Clear previous data
var row = tableBody.insertRow();
row.insertCell(0).textContent = document.getElementById('mailType').selectedOptions[0].text;
row.insertCell(1).textContent = calcResult.weightOz.toFixed(2) + ' oz';
row.insertCell(2).textContent = document.getElementById('dimensions').value || 'N/A';
row.insertCell(3).textContent = document.getElementById('serviceType').selectedOptions[0].text.replace(/_/g, ' ').replace('firstclass', 'First-Class');
row.insertCell(4).textContent = document.getElementById('destinationZip').value || 'N/A';
row.insertCell(5).textContent = '$' + calcResult.cost.toFixed(2);
}
// Initial calculation on page load
document.addEventListener('DOMContentLoaded', function() {
// Adjust UI for package weight unit visibility
var mailTypeSelect = document.getElementById('mailType');
var packageWeightUnitGroup = document.getElementById('packageWeightUnitGroup');
mailTypeSelect.addEventListener('change', function() {
if (this.value === 'package') {
packageWeightUnitGroup.style.display = 'block';
} else {
packageWeightUnitGroup.style.display = 'none';
// Reset unit to oz if not package type
document.getElementById('packageWeightUnit').value = 'oz';
}
updateCalculator(); // Recalculate when type changes
});
// Set initial state based on default 'letter'
if (mailTypeSelect.value !== 'package') {
packageWeightUnitGroup.style.display = 'none';
} else {
packageWeightUnitGroup.style.display = 'block';
}
updateCalculator();
});
// Need to add the canvas element to the HTML for the chart
// Find the calculator form and insert the chart container after it.
var calculatorForm = document.getElementById('stampCalculatorForm');
var chartContainerHTML = `
Visual representation of postage cost components or estimates.
`;
calculatorForm.insertAdjacentHTML('afterend', chartContainerHTML);
// Need to add the table element to the HTML
var articleSection = document.querySelector('.article-section');
var tableHTML = `